If you can get into recovery, then don't flash any updates. You'll lose recovery and be in a worse off place. Steps I suggest.
1) Wipe data using recovery and try booting again
2) Flash an OEM base rom (Sotard for ICS or one of the original GB based roms). Less chance of it being a software issue. Avoid any themed or tweaked roms.
3) Use adb while in recovery and check your system and data partitions for errors.
4) Last resort, flash a .cab file. I can tell you from experience, if the above does not work, this will most likely not either. You'll still be stuck not booting and need to figure it out, plus you will have lost recovery and the ability to ADB into your phone.